This invention relates generally to microwave and convection ovens, and more specifically, to methods and apparatus for configuring oven controls.
Known microwave ovens include a programmable controller, such as a microprocessor, for controlling oven operations based on operator inputs. Such microprocessors include a read only memory (ROM) unit, sometimes referred to herein as an on-board ROM. The control program is stored in the on-board ROM. Control parameters, cooking parameters, and features data also are stored in the on-board ROM. An exemplary control parameter is a bit set to one or zero to indicate whether a sound, or beep, feature of the microwave should be activated, i.e., on/off. Exemplary cooking parameters include preprogrammed cooking algorithms designating power levels and times. Exemplary features data include data relating to key panel features, such as a POPCORN feature which enables an operator to simply select POPCORN on the key panel to cook popcorn.
Since different model microwave ovens typically have different characteristics such as different cavity sizes, output powers, and control features, the control and cooking parameters and data vary for each model. If any changes are desired or required to the control parameters, cooking parameters, or feature data, the microprocessor supplier generally must fabricate a microprocessor having the modified parameters and data stored in the on-board ROM. Incorporating such changes into the on-board ROM often takes many weeks to complete. Such delay may result in lost sales due to customer demands for certain modifications.
For example, if a particular model requires a BAGEL feature rather than a POPCORN feature, the parameters and data stored in the on-board ROM must be changed. Making such changes to the on-board ROM, however, can take weeks to complete.
Some microprocessor fabricators do offer special microprocessors for more quickly incorporating changes into the on-board ROM. Such special microprocessors, however, are much more expensive than the standard production processors. Especially in high volume production, such as with microwave ovens, the added costs associated with the more expensive microprocessors typically prohibits use of such processors.
It would be desirable to provide a controller for use in microwave ovens that enables changes to be quickly made to the control parameters, cooking parameters, and feature data, yet which also does not have prohibitive costs.
These and other objects may be attained by a control unit that includes an external memory storage for storing replacement control parameters, cooking parameters, and feature data for a microwave oven. More particularly, and in one embodiment, the control unit includes a pre-programmed microprocessor coupled to a key panel and a display. The controller also is coupled, for example, to a power supply, sensors, and power switches.
The control microprocessor, as is known in the art, includes an on-board memory unit, e.g., a read only memory (ROM), for storing the control program. Control parameters, cooking parameters, and feature data also are stored in the on-board ROM. Under the control of the control program, and using the parameters and data stored in the on-board ROM, the microprocessor is configured to control, for example, energy output levels and cooking time based on the operator inputs.
The control unit may also include an external model configuration read only memory (EMCR) coupled to the control microprocessor via an external bus. The EMCR also has control parameters, cooking parameters, and feature data stored therein. The parameters and data stored in the EMCR can differ in many respects from the parameters and data stored in the on-board memory.
The control microprocessor and the EMCR, in one embodiment, are located on a printed circuit board. The EMCR is removably inserted into a plug connector which is electrically connected to the microprocessor. In operation, and upon initialization of the control microprocessor, the microprocessor attempts to read parameters or data from the EMCR. If the EMCR has been inserted into the connector, the attempt to read from the EMCR will be successful and the processor then uses the parameters and data stored on the EMCR. If the attempt to read from the EMCR is not successful, then the EMCR has not been inserted into the connector and the processor uses the parameters and data stored in the on-board ROM.
The above described control unit enables making changes to microwave oven operations by simply installing an EMCR having the parameters and data stored therein. The EMCR stored parameters and data can be used on models fabricated while a new processor is being designed/revised, tested, and fabricated. Once the new processor is available, then the EMCR is not needed, i.e., the EMCR is no longer installed on circuit boards fabricated subsequent to availability of the new processor. The control unit therefore enables fast and easy conversion to modified parameters and data, and is believed to be less expensive than using specialized processors that allow for reconfiguration of the parameters and data stored in the on-board memory.